With the constant progress of scientific technology, people's reliance on various kinds of electronic apparatuses also increases. Electronic products, such as computers and notebook computers, have internal elements that tend to produce a high amount of heat during operation thereof. The produced heat must be timely removed from the electronic products to avoid the problem of overheating. Therefore, most electronic products are internally equipped with a fan, so that the electronic products in operation can always maintain at a temperature within the working temperature range set for them.
FIG. 1 shows a conventional parallel fan structure 1 that includes two or more fan frames 10. The fan frames 10 are parallelly arranged side by side to contact with one another. When a fan operates, the motor thereof will inevitably produce vibration as a result of the torque of the motor. For the parallel fan structure 1 that includes two or more parallelly arranged fans, the produced vibration is increased. While the conventional parallel fan structure 1 can produce increased airflow to carry more heat away from the interior of the electronic product, the frames 10 of the parallelly connected fans in the parallel fan structure 1 also produce serious resonance effect when all the fans operate at the same time, this is because the vibration base-frequency of the fan wheels 11 will mutually influence on one another. In addition, the parallel fan structure 1 is subjected to serious dipole noise generation due to dipole-dipole interaction between fans arranged in pairs.
Accordingly, the conventional parallel fan structure has the following disadvantages: (1) the fans thereof produce increased vibration when they operate; and (2) it produces serious noise due to dipole-dipole interaction.
It is therefore tried by the inventor of the present invention to develop an improved fan structure that can eliminate the problems in the conventional parallel fan structure.